Telephone return-time signal



July 14, 1925. 1,546,311

A. R. PATTERSON ET AL TELEPHONE RETURN TIME SIGNAL Filed Aug 10, 1923 INVEN TORS ATTO EY.

Patented July 14, 1925.

UNITED STATES i I A 1,546,311 N bFFiciz' ARTHUR R. PATTERSON AND SAMUELJ. TOMLINSON, JR., OF FAIRLAND INDIANA.

TELEPHONE RETURN-TIME SIGNAL.

To all whom it may concern:

Be it known that we, ARTHUR R. PATTER- SON and SAMUEL J. TOMLINSON, Jr., citizens of the United States, residing at Fairland, in the countyof Shelby and State of Indiana, have invented a new and useful TelephoneReturn-Tiine Signal, of which the following isa specification.

It is the object of our invention to indicate the time when a personwill return who is away from his home or office when called on thetelephone.

In carrying out our invention, we provide indicating devices, preferablysubstantially duplicates, at the subscribers sub-station and at thecentral oflice. These indicating devices are in the nature ofmilli-ammeters, but preferably have clock-faces for the more convenientindication of time. subscribers sub-station there is a two-point switchwhich the subscriber throws to the signaling instrument when he is aboutto leave his home or oflice, a battery for supplying the signalingcurrent, a push-button for closing a local circuit through a batteryfrom a subscribers indicating instrument, which local circuit has aresistance corresponding to that of the line circuit and a rheostatwhich can be adjusted to allow different currents to flow to get anydesired in dication on the subscribers signaling device such as oclock,by way of example. The subscribers signaling device and the line hasalsoan adjustable resistance which can be set to raise the resistance ofthe circuit through the line and signaling instrument to a predeterminedvalue, so that this circuit will be the same for all subscribers lines.At the central station, the signaling instrument is suitably connected,as to segments on' the point of the plug, so that as the operator startsto put the plug in the jack she may temporarily complete a circuitthrough her signaling device. If the signaling device at the sub-stationof the subscriber being called is set, she-does complete such circuit,which is supplied from the battery at the subscribers sub-station, andwhich causes the signaling device at the central station to give thesame indication as that for which. the signaling device at thesubscribers substation is set.

The accompanying drawing illustrates our invention: The single figure ofthe drawing is a diagram showing the necessary connecsub-station.

At the tions and elements of'our invention, at the central station andat one subscribers substation.

The two line wires 10- and 11 lead from the two contacts 12 and 13 ofthe corresponding jack at the central stationto the telephone instrument14.- at the subscribers At the subscribers sub-station the lin'ewire 11leads to" a two-po'int'switch 15, having two contact points 16 and 17.lVhen the switch engages the contact 16, it connects the line wire 11'to the telephone 14. 'lVhen the switch 15 engages the contact .111, itconnects theline-wire 11 to the subscribers signaling device. The otherline wire-10 is permanently connected to both the telephone sub-station1 1 and the signaling device. .f V Thelsubscribers signaling device hasasuitable current-measuring device, in the nature of a milligammeter.Thismay take any desiredgformg but for simplicity of diagrammaticillustration; this milli-ammeter is shown as having a solenoid 20 whichacts on a. core 21 to turn a hand or pointer 22 over a.d1al"23'aga1nstthe-opposition of a spring 24;and the-dial 23 is shown as a' clock-facedial, for'the convenient indication oftime signals. This particular typeof current-measuring device is shown merely because it is the easiest toillustrate, in connection with the desiredcomplete-circle dial.

At the subscribers sub-station. there is also-a source-of current, suchas a battery 25, conveniently formed of several dry cells. This batterysuppliesthe signaling current which goes out from this particularsubstation, togive the signal to the operator at central; and likewisesupplies the current for a local settingcircuit by which the resistanceof the signaling circuit to the central operator may be adjusted to givethe desired indication on her vmilli-ammeter. This setting circuit isof-the same resistance as the signaling circuit'through the line, andthere is an adjustinguheostat 26 which is included as .part both of thislocal circuit and of the signaling circuit through the line. Theconnections: for obtaining this may be considerably varied, and We haveshown one simple set ofconnections merely by way of illustration." Inthis illustrative set of connections, one terminal ofthe battery 25andone terrninal oftherheostat 26 are connected by a wire 27;; theotherterminal of of the adjustable resistance 30 is connected by a wire31 to one terminal of a push-but ton 32; the other terminal of thepush-button 32 is connected by a wire 33 tothe-other terminal of thebattery the wire 33 also connects that terminal of the battery 25 'tothe contact'point 17 ofthe double-throw switch 15; the wire 29 is alsoco-nnected'by a; wire 34 to one terminal of a second adjustableresistance 35; and the other terminal of this second adjustableresistance 35 is connected by a wire 36'tothe line wire 10. A hen thepush-button 32 is depressed, it closes-the local setting circuit, whichis from the battery 25, through the wire 27, rheostat 26, wire 28,solenoid 20, wire 29, adjustable resistance 30, wire 31, push-button 32,and wire 33, back to the battery 25. *Vith the push-button 32un-depressed, and the twopoint switch 15 on the contact point 17, thereis: a potential signaling circuit from-the battery 25 through the wire27, rheostat 26, wire 28, solenoid 20, wire 29, wire 34, adjustableresistance '35, wire36, line wire 10, the connections-shortly to bedescribed and located at the operators central station back to the linewire 11, then through the switch 15, con-tact point 17, and wire 33 backto the battery 25. w The adjustable resistance 35 is provided to adjustthe signaling circuit for the subscribers line to a predetermined value,which value will be the same for all subscribers lines, so that signalswhich come in to the central station will not be disturbed byvaryingresistances of the lines. For this same purpose of preventingdisturbance and getting proper signals, the adjustable resist ance isadjusted to make that part of the local circuit from the wire 29 throughsuch adjustable re'sistanceto the battery 25 equal to the aforesaidpredetermined value; so that the resistance in this local circuit willbe the same as that of the signaling circuit through the line. Theadjustableresistance 3O may be calibrated'at the'facto'ry, to set it forthis predetermined value; but the adjustable resistance mustbeicalibrated by the electrician who installs the particular instrufment. As a result of this, adjustment of the rheostat 26 to any pointequally adjusts thev resistance of the line signaling circuit and theresistance of the local setting circuit.

At the central station there is'also, a current-measuring device,likewise in the nature of a milli-ammeterk This is preferablysubstantially identical with that at the subscribers sub-station. I Thisalso is illustrated in the same diagrammaticway, being shown as having asolenoid'20 which acts on a core 21 to turn a hand or pointer 22 over adial23. The dial23, like the dial 23, is

shown as a clock-face dial, for theconvenient indication of timesignals. The milliammeter at the central station is arranged tobeconnected across the line 10-11 temporarily at the beginning of theinsertion oi the calling plug 40' into the jack 1213;

1 to completethe signaling circuit from the gaging the jack'contacts 12and 13' as the calling plug 40 is started into the" jack. Theseadditional segments and 46 at the point of the calli'ngplug areconnected by wires '47 and 48 to the two terminals of the solenoid 20. 1i

In operation, the two-point switch 15 at the subscribers v sub-stationis normally on the Contact 16, to render his signaling deviceinoperative and to connect his'telephone 14 i or ordinary calling andtalking in the usual manner. With this connection, when'the operatorplugs into this subscribers jack 12-13, the temporary engagement of theplug point-segments and'46 with the jack contacts 12v and 13 causes nocurrent flow i through the solenoid 20" of the operators milli-ammeter,and she gets no movement of the pointer 22; so that she pushes her plugstraight through to cause the segments 41 and 42 to engage the jackcontacts 12 and 13,

and thus completes the regular telephone circuit. V

On the other hand, when the subscriber leaves his otfice, with theexpectation of being back at some definite time, he shifts his switch 15from the contact 16 to the contact 17, to disconnect his telephone fromthe line and connect his signaling device to the line. Further, eitherbefore or after thus shifting the switch 15, the depresses the pushbutton 32, and adjusts his rheostat 26 to vary the resistance of hislocal setting circuit until the current-flow thereinv is just suflicientto produce the desired indication bv the pointer 22 on the dial 23., Inother words, while holding the push-button 32 depressed, he shiftsthe'rheostat 26 in one direction or the other until, he sees that thepointer 22 gives the indication'wanted say 10 oclock, Leavingtheirheostat 26 so set, he releases the pushbutton 32, and goes on hisway. I

- When now the operator attempts to call this subscriber, and in pushingin her call ing plug 40 connects the point-segments 45 and 46 to thejack contacts 12 and 13, she completes the line signal circuit abovedescribed. The current in this circuit comes from the battery 25 at thesubscribers substation and flows through the solenoids 20 and 20' ofboth the milli-ammeter at the subscribers sub-station and themilli-ammeter at the central station. The total resistance in thiscircuit is the same as that which is in the subscribers local circuit.

Therefore, the current coming from the same battery, (which in themeantime has had no opportunity to change materially in voltage,) thesolenoid 20 at the central station pulls down its core 21 to produce anindication by the pointer 22 corresponding to that which the subscriberhad obtained on his milli-aimneter-which we assumed was 10 oclock. Theoperator at central, on seeing this indication, does not complete hercall, but pulls out her calling plug 20, and announces to the subscriberwho is calling that the subscriber being called is out and will returnat 10 oclock.

When the subscriber returns who has set his sub-station for signaling,he throws the switch 15 back to the contact point 16, and is ready toreceive calls in the usual manner.

WVe claim as our invention:

1. A telephone return-time signal, comprising a current-measuring deviceat the subscribers sub-station, a current-measuring device at thetelephone central station, means for connecting the lattercurrentmeasuring device to the line leading to the subscriberssub-station, a source of current at the subscribers sub-station, aswitch for connecting the subscribers line at will to his telephoneinstrument or to said source of current and current-measuring device inseries, a switch for completing a local circuit from said batterythrough said currentmeasuring device at the subscribers sub-stationindependently of the line, and a rheostat in the circuit of said batteryand said current-measuring device at the subscriber's sub-station forvarying similarly either circuit which may be completed therethrough.

2. The combination set forth in claim 1, with the addition that saidmeans for connecting the current-measuring instrument at the centralstation to the line leading to the subscribers sub-station comprisessegments on the point of the operators calling plug and arranged topreliminarily engage the contacts of the jack of that subscribers line.

3. The combination set forth in claim 1,

with the addition that said current-measuring instruments haveclock-faces.

at. The combination set forth in claim 1, with the addition that saidlocal circuit contains a resistance which makes the resistance of saidlocal circuit substantially equal to that of the circuit which may becompleted through the line and the currentmeasuring instrument at thecentral station.

5. The combination set forth in claim 1, with the addition that saidlocal circuit contains a resistance which makes the resistance of saidlocal circuit substantially equal to that of the circuit which may becompleted through the line and the current-measuring instrument at thecentral station, and with the further addition that said resistance inthe local circuit is adjustable.

6. The combinationset forth in claim 1, with the addition of aresistance in the connection between the subscribers line and saidcurrent-measuring device at the subscribers sub-station.

7 The combination set forth in claim 1, with the addition of aresistance in the connection between the subscribers line and saidcurrent-measuring device at the subscribers sub-station, and with thefurther addition that said resistance is adjustable.

8. The combination set forth in claim 1, with the addition of aresistance in the connection between the subscribers line and saidcurrent-measuring device at the subscribers sub-station, and with thefurther addition that said local circuit contains a resistance whichmakes the resistance of said local circuit substantially equal to thatof the circuit which may be completed through the line and thecurrent-measuring instrument at the central station.

9. The combination set forth in claim 1, with the addition of aresistance in the connection between the subscribers line and saidcurrent-measuring device at the subscribers sub-station, and with thefurther addition that said local circuit contains a resistance whichmakes the resistance of said local circuit substantially equal to thatof the circuit which may be completed through the line and thecurrent-measuring instrument at the central station, both saidresistances being adjustable.

In witness whereof, we have hereunto set our hands at Fairland, ShelbyCo., Indiana, this 8th day of Aug, A. D. one thousand nine hundred andtwenty three.

ARTHUR R. PATTERSON. SAMUEL J. TOMLINSON, JR.

